Table 2:

Causes of peripheral eosinophilia

Primary	Clonal neoplasm ○ Myeloid and lymphoid neoplasms (rearrangement of PDGFRA, PDGFRB, FGFR1, PCM1-JAK2, ETV6-JAK2 or BCR-JAK2) ○ Chronic eosinophilic leukemia ○ Systemic Mastocytosis with clonally driven eosinophil proliferation ○ Other myeloproliferative process in which clonal eosinophil proliferation plays a role (ie: CML, AML, etc.)
Secondary	Allergic ○ Allergic Bronchopulmonary Aspergillosis ○ Allergic Rhinitis ○ Asthma ○ Atopic Dermatitis ○ Drug allergy
	Gastrointestinal ○ Eosinophilic GI disorders ○ Inflammatory Bowel Disease ○ Celiac
	Hematologic / Oncologic ○ Graft versus Host Disease ○ Cytokine-driven eosinophil proliferation in Systemic Mastocytosis ○ Lymphocytic-variant Hypereosinophilic syndrome
	Infectious ○ Parasitic ○ Fungal ○ HIV
	Inflammatory ○ Eosinophilic granulomatosis with polyangiitis ○ Wells syndrome ○ Polyarteritis nodosum ○ Less commonly: sarcoidosis, rheumatoid arthritis, IgG4 disease
	Immunologic ○ Gleich Syndrome ○ Hyper-IgE syndromes ○ Wiskott Aldrich Syndrome ○ Omenn’s Syndrome ○ Less commonly: ZAP70 deficiency, ALPS, LRBA deficiency, PGM2 deficiency
	Respiratory ○ Acute or chronic eosinophilic pneumonia
Idiopathic	No detectable cause despite investigation of secondary and primary causes